1. Field of the Invention
The present invention relates to a visual inspection apparatus used to inspect the appearance of a workpiece, a visual inspection method, and a peripheral edge inspection unit that can be mounted on such a visual inspection apparatus and used to inspect the peripheral edge of the workpiece.
2. Description of Related Art
When patterns, such as circuits, on a workpiece, such as a semiconductor wafer, are formed, a visual inspection apparatus that inspects the existence of a defect on the surface of the workpiece is used. As this type of visual inspection apparatus, there is an inspection apparatus (for example, refer to Patent Document 1) that oscillates and rotatably holds a workpiece, has a macro-inspection section that allows an inspector to visually inspect the surface of the workpiece (macro inspection), and a micro-inspection section that acquires an enlarged image of the workpiece to allow inspection (micro inspection), and that enables such macro inspection and micro inspection by use of one apparatus.
Further, when circuits, etc. are formed on a workpiece, warpage or internal stress may be caused in the workpiece due to heat treatment, etc. If such warpage and internal stress become large, the workpiece may be fractured during manufacture of the circuits. Thus, a technique of enlarging and observing the peripheral edge of the workpiece in advance, thereby inspecting the existence of cracks which may becomes fractures in the future, is known. As a visual inspection apparatus used to inspect the peripheral edge of the workpiece (peripheral edge inspection), there is an inspection apparatus (for example, refer to Patent Document 2) including a support that rotatably supports a workpiece, a peripheral edge imaging section that continuously captures images of the peripheral edge of the workpiece, and a peripheral edge illumination device that illuminates the peripheral edge.
[Patent Document 1] JP-A-2004-96078
[Patent Document 2] JP-A-2003-243465
However, in order to carry out the macro inspection, micro inspection, and peripheral edge inspection, there are problems in that a wafer must be replaced and moved by a machine, a loader, etc., between the visual inspection apparatus disclosed in Patent Document 1, and the visual inspection apparatuses disclosed in Patent Document 2, causing prolonged takt time. Further, when one visual inspection apparatus is attached to another visual inspection apparatus externally, transport time can be shortened. However, replacement of a workpiece is required even in such a case. Moreover, the installation area as the whole apparatus is not different from when apparatuses are installed independently.